Technical Field
The present invention relates to a cover glass which is provided on an observer side of a display device, and a method of manufacturing the same. In addition, the present invention relates to the display device provided with the cover glass.
Background Art
Conventionally, a technique has been known in which a cover glass for protection of a display surface of a display device is provided on an observer side of the display device such as a liquid crystal display or an organic EL display. In a case in which the display device is equipped with a touch panel function, the cover glass also serves a role of protecting the display device and a touch panel sensor which is provided on the observer side of the display device. Incidentally, another technique has been also known in which a cover glass and a touch panel sensor are integrally configured.
Recently, portable terminals equipped with display devices have been remarkably popular such as a smart phone and a tablet PC. The portable terminal is required to have durability with respect to a drop impact generated in the use environment. Accordingly, there is a demand for high strength in a cover glass that protects the display device to be capable of withstanding the impact frequently generated. Under such circumstances, Patent Document 1, for example, proposes a method of configuring a cover glass using a tempered glass which includes a compressive stress layer on which a compressive stress is generated being formed on a surface thereof.
In Patent Document 1, the cover glasses having dimensions corresponding to respective dimensions of individual display devices are produced by dividing the large tempered glass into individual pieces. Meanwhile, the compressive stress layer of the tempered glass is formed on the glass surface by chemical treatment, or heat treatment. Accordingly, a tensile stress layer in which a tensile stress is generated is exposed on a side surface of the cover glass to be obtained in a case in which the large tempered glass is divided as in Patent Document 1. Thus, it is considered that it is difficult to manufacture a cover glass having a sufficient strength on a side surface thereof according to the method described in Patent Document 1.
Meanwhile, proposed is a method of providing resin on a side surface of a cover glass to enhance the strength on the side surface of the cover glass. For example, Patent Document 2 proposes a method of framing an outer peripheral surface of a cover glass including a side surface of the cover glass with a plastic membrane. An injection molding method, a dispensing method, a spray coating method, a roller coating method or the like is proposed as the framing method.
Patent Document 1: Japanese Patent Application Laid-Open No. 2012-88946
Patent Document 2: Japanese Patent Application Laid-Open No. 2012-111688